The present invention relates to a transportation system of a floated-carrier type and, more particularly, to a transportation system of a floated-carrier type wherein, when a carrier is stopped at a station, the carrier's battery can be automatically charged.
With the aim of increasing office or factory automation, such transportation systems have, in recent times, been installed in some buildings. Such systems are used to transport slips, documents, cash, samples, or the like, between a plurality of locations within the buildings.
In order to avoid spoiling the working environment of the offices or factories, it is essential that such transportation systems do not produce dust or an excessive level of noise. Thus, in one such conventional transportation system, described in U.S. patent application Ser. No. 7/036,175, filed on Apr. 8, 1987 by the inventors hereof, a carrier is kept floating, in a non-contact manner, from a guide rail, by means of an electromagnetic attractive force acting between the carrier and the rail, when the carrier is propelled along the rail.
In this transportation system, various types of electrical devices are mounted on a carrier. More specifically, an electromagnet applying an electromagnetic attractive force to the carrier, and a control unit for controlling the magnet are mounted on the carrier. A battery for supplying a current to the magnet and control unit is mounted on the carrier. The battery preferably has a large capacity, so that the carrier can be continuously operated over a long period of time.
However, since a large-capacity battery is quite heavy, then if it is mounted on the carrier, the total weight of the carrier increases considerably. The electrical power required to enable the carrier to float also increases, which represents a considerable waste of energy.
On the other hand, a small-capacity battery is light weight, hence the energy required to enable the carrier to float can be greatly reduced. However, such a battery requires frequent replacement, in order that the carrier can be operated continuously over a long period of time. It requires a long period for replacing the battery, so that a maintenance for replacement is cumbersome. (Note that an apparatus for replacing the battery of the carrier in the transportation system is disclosed in Japanese Patent Disclosure (Kokai) No. 49-15112.)
It is therefore difficult to realize a transportation system wherein a carrier does not waste a large amount of energy, and which can be operated continuously over a long period of time without the need for frequent replacement of its battery.
In addition, if the weight of the carrier increases considerably, the electrical power to accelerate the carrier would be increased. Also, the carrier is magnetically suspended in a non-contact manner, from a guide rail. That is, the guide rail receives the total weight of the carrier. In case the weight of the carrier increases considerably, it is required that the guide rail be rigidly suspended to the ground. Therefore, propelling energy and the cost of ground facilities would be increased.